As written in the title, there's a specific word that is not too common in English that's used to describe the feeling you can get when you finally resolve your long-term disdain for someone, or reaching some sort of civility between you and them.
I can't remember it but I would know it if I saw it.
He attained [a feeling of] ____ after talking to his estranged father after many years.
I'm not looking for synonyms of peace or closure, and nothing on Thesaurus.com has helped me. It is a very specific, unique word. It's like closure, peace of mind, or inner peace, but I've only seen it used in the context of sunsetting a toxic, detached relationship.
The actual meaning of the word I was looking for was peace of mind for any period of negativity. It's not necessarily unique to interpersonal relationships.